A variety of route planning systems and devices are known. Some are provided on general-purpose computer systems such as personal computers or on the World Wide Web, while others are provided as part of dedicated devices such as automobile navigation systems. The traveler, who is typically a driver, specifies a starting point, a destination and optionally a number of intermediate way-points, and the route planning system automatically plans a suitable route.
A typical automobile navigation system uses GPS to track the location of the car. It may provide automatic route planning, or it may only allow the driver to enter a route planned by other means. In any case the navigation system typically assists the driver in following the route by displaying local mapping data keyed to the car's current location and issuing directions to the driver to follow the route. It may also utilize synthesized spoken instructions.
Route planning systems suffer from a number of problems. Route planning is often not integrated with an automobile navigation system where it is needed, requiring manual and laborious entry of way-points. Where it is integrated, the limited size and resolution of navigation system screens make the entry of locations awkward.